Vertical wafer carrier handling apparatus

ABSTRACT

An apparatus for efficiently and safely loading, unloading and transporting vertically oriented wafer carriers. The apparatus includes a body having a front and a back face, a top portion and a first and a second side, two horizontally aligned handles mounted to respective first and second sides on the front face of the body. The apparatus further includes an arm having a fixed end attached to the top portion of the back face of the body and a free end containing a slot, extending from the free end toward the fixed end, of dimensions suitable to slidably receive the carrier handle and to restrain movement of the carrier parallel to the back face of the body and a top surface. The top surface has a recessed portion suitable for retaining the handle of the wafer carrier and restraining movement of the carrier perpendicular to the back face and the recessed portion is sufficiently proximate to the back face that the back face will prevent the removal of a wafer contained in the carrier when the carrier handle is retained in the recessed portion. In a preferred embodiment, the body is substantially rectangular and has two rectangular portions cut out symmetrically about the vertical centerline of the body to reduce the weight of the apparatus and which define a middle support and a bottom portion.

This is a continuation of copending application(s) Ser. No. 08/595,746filed on Feb. 2, 1996, now U.S. Pat. No. 5,658,028.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices useful for lifting and removingobjects from spaces where access is restricted. More particularly, thepresent invention relates to detachable wafer carrier handle assembliesand combinations thereof for use in loading and unloading vertical wafercarriers into and out of equipment and transporting the wafer carriersbetween equipment.

2. Description of the Invention Background

Semiconductor devices such as transistors, are commonly mass produced bysimultaneously forming a plurality of semiconductor devices on a wafershaped substrate, or wafer, composed of a semiconductor material, suchas monocrystalline silicon. The processed wafers are then cut up toseparate the individual devices for use in a variety of applications.Many of the processing steps in the formation of semiconductor devicesare not amenable to continuous processing and, therefore, must beprocessed in batch type processing stages, which tend to lowerproduction capacity due to process downtime involved with loading,unloading and transporting the batches. Processing equipment has beendesigned to increase production capacity by simultaneously orcontinuously treating a number of wafers in a semi-batch processingmode. The wafers are processed in bulk through the use of wafer carriersthat have been designed to hold and separate a plurality of wafersallowing for the simultaneous or continuous processing of the batch. Thewafer carriers also serve to minimize the need for human contact withthe wafers during processing which could result in contamination of thewafers. Various designs and material of construction are used in thewafer carriers depending upon the processing stages in which the wafercarrier is to be used, but in most carriers generally consist of a basecontaining a plurality of slots or grooves that serves to separate thewafers in a cassette-type arrangement.

Two different types of materials are commonly used for wafer carriers inthe industry. In high temperature processing steps, greater than about200° C., wafer carriers are often made from a plurality of quartz orother temperature resistant rods that form a "basket" or "rack" forsupporting the wafers. In low temperature processing steps, wafercarriers are typically made of molded plastics, such aspolytetrafluoroethylene (Teflon®) or polypropylene. In addition totemperature considerations, the carrier design is dependent upon theprocessing step in which the carrier is used. Some carriers, known aslow profile carriers, are designed to provide relatively unrestrictedaccess to the wafers within the carrier. Other carriers, known as highprofile carriers, are designed to more fully enclose and protect thewafers.

One limiting aspect of the overall production capacity of thesemiconductor devices is the time involved in loading and unloading thewafer carriers in the equipment for each batch type processing stage andtransferring the wafer between stages. In addition, these handlingoperations also greatly increase the potential for physical damage toand contamination of the wafers. In most instances, the wafers aregenerally stored and transported in the carriers in which the wafers arein a vertically upright, horizontally spaced array. However, in a numberof processes the faces of the wafers must be horizontally oriented andthe wafers must be loaded into the equipment using a vertical wafercarrier in which the faces of the wafers are oriented horizontally, in avertically spaced array.

Vertical wafer carriers typically have one end that contains a handle toenable the carrier to be lifted in a stable manner. The opposite end ofthe carrier is designed so that the carrier can stand on end. The waferprocessing equipment typically must be loaded from either the top or theside of the equipment. In top loading equipment, the vertically orientedcarrier can be lowered into the processing equipment by the handle ofthe carrier in a stable, controlled manner. However, when loading avertical carrier horizontally into side loading equipment, the verticalcarrier generally can not be held by the handle from above the carrierwithin the confines of the processing equipment and the carrier must besupported in a different manner. Supporting the carriers from below theopposite end of the carrier or the handle, or by the sides impartsinstability to the carrier and requires precise control of the carrierto avoid tilting the carrier during the loading and unloading operationthat could result in dumping the wafers out of the carrier or wedgingthe carrier in the equipment.

One prior method of manipulating carriers having an open handleextending from their upper surface included the use of a removablehandle. Such handle included a T-shaped frame having a single handleextending from one side of the vertical member of the T. Two spacedelongated wedge members extend from the other side of the horizontalmember of the T. The wedge members serve to engage the handle on thecarrier. This method, however, was flawed in that it required a user tomanipulate a rather heavy carrier filled with wafers with only one hand.This proved to be strenuous and has led to dropping of carriers andwafers.

The present invention is directed to providing an apparatus toefficiently and safely load and unload a vertically oriented wafercarrier in a substantially horizontal direction which overcomes, amongothers, the above-discussed problems so as to increase the stability,efficiency and safety of the loading and unloading of verticallyoriented wafer carriers.

SUMMARY OF THE INVENTION

The above objects and others are accomplished by a wafer carrierhandling apparatus in accordance with the present invention. The wafercarrier handling apparatus of the present invention is provided forefficiently and safely loading, unloading and transporting verticallyoriented wafer carriers. The apparatus includes a body having a frontand a back face, a top portion and a first and second sides, and twohorizontally aligned handles mounted to respective first and secondsides on the front face of the body. The apparatus further includes anarm having a fixed end attached to the top portion of the back face ofthe body and a free end containing a longitudinal slot extending fromthe free end toward the fixed end, and having dimensions suitable toslidably receive the carrier handle and to restrain movement of thecarrier parallel to the back face of the body and a top surface. The topsurface of the arm has a recessed portion suitable for retaining thehandle of the wafer carrier and restraining movement of the carrierperpendicular to the back face and the recessed portion is sufficientlyproximate to the back face that the back face will prevent the removalof a wafer contained in the carrier when the carrier handle is retainedin the recessed portion. In a preferred embodiment, the body issubstantially rectangular and has two rectangular portions symmetricallycut out about the vertical centerline of the body to reduce the weightof the apparatus and which defines a middle support and a bottomportion. Also in a preferred embodiment, the length and width of thebody are no larger than the length and width of the wafer carrier, so asto enable the apparatus to be used in equipment where access is limitedto the area occupied by the carrier.

Accordingly, the present invention provides effective solutions to theproblems present in the handling of bulk quantities of wafers in avertical wafer carrier. In particular, the subject invention greatlyimproves the stability and safety of the handling operations, whilesimplifying the procedure for handling. Also, the use of the presentinvention involves a sequence of one dimensional steps that allow thepresent invention to be more easily integrated into a fully automatedprocedure. Thus, the present invention can provide for a reduction inthe overall cost associated with the production of the wafers byproviding for a more efficient procedure to move bulk quantities ofwafers into, out of and between batch processes. These and otherdetails, objects, and advantages of the invention will become apparentas the following detailed description of the present preferredembodiment thereof proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the present invention will be described ingreater detail with reference to the accompanying drawings, wherein likemembers bear like reference numerals and wherein:

FIG. 1 is a front perspective view of a preferred embodiment of thepresent invention;

FIG. 2 is a back side view of the body member in a preferred embodimentof the present invention;

FIG. 3 is a top view of a preferred embodiment of the present invention;

FIG. 4 is a top view of a preferred embodiment of the present inventionholding a cassette containing wafers; and,

FIG. 5 is a side view of a preferred embodiment of the present inventionsupporting a wafer carrier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The operation of the wafer carrier handling apparatus 10 will bedescribed generally with reference to the drawings for the purpose ofillustrating present preferred embodiments of the invention only and notfor purposes of limiting the same. The apparatus 10 includes a body 20,two handles 40 attached to the front face of the body 20 and an arm 50attached to the back face of the body 20 for supporting a wafer carrier70. A preferred embodiment is described with reference to a wafercarrier 70 having a handle end 74 with a carrier handle 72 attachedthereto, and a support end 76. Additionally, the carrier 70 can furtherinclude a carrier handle support 78 attached between the carrier handle72 and the handle end 74 and alignment tabs 75 and slots. The carrier 70may have approximate dimensions of, for example, 8.5 inches wide by 8inches high by 7.5 inches deep, for an eight inch diameter wafer.

In a preferred embodiment, the body 20 is substantially rectangularlyshaped having a front face 22 and a back face 24 that can bedimensionally characterized by a width and a length The carrier 70 canalso be dimensionally characterized as having a width and a length.Preferably, the length and the width of the body 20 are no larger thanthe length and the width of the wafer carrier 70, as shown in FIGS. 4and 5, so that the apparatus 10 can be used to load and unload a wafercarrier 70 from equipment in which the maximum area available is definedby the size of the wafer carrier 70. Preferably, the body 20 isconstructed from a solid piece of material having a uniform thickness,such as 1/2" thick polypropylene, in which two large rectangularportions 21 symmetrically disposed about the vertical centerline, B--B,of the body 20 have been cut out so as to define a top portion 26, abottom portion 28, a middle support 30 and first and second sides, 32and 34, respectively. The use of body 20 containing cut out portions 21is preferred over a complete solid body 20, so that higher strengthmaterial, which in most instances involves higher densities, can be usedto construct the body 20 without substantially increasing the overallweight of the apparatus 10. It is also preferred that edges defining thecut out portions 21 are parallel to the perimeter of the body 20 and thecorners are rounded in order to minimize the potential for uneven forcedistributions when a wafer carrier 70 is lifted.

The body 20 preferably contains a middle support 30 disposed about thevertical centerline, B--B, to provide structural strength in the planecontaining the arm 50 and to prevent the wafers 80 from sliding out ofthe wafer carrier 70 during the handling of the wafer carrier 70 withthe apparatus 10. The first and second sides, 32 and 34, respectively,are preferred to provide structural support for the body 20 near thehandles 40 or alternatively for mounting the handles 40. The body 20 canalternatively be any other geometric shape, such as circular, whichwould be suitable to achieve the objective of the invention and can beconstructed using separate members for the top portion 26, the bottomportion 28, the middle support 30 and the two sides, 32 and 34,respectively, and for combinations thereof.

In a preferred embodiment, recessed slots 36 are provided in the backface 24 of the body 20 to mate with alignment tabs 75 on the carrier 70and to provide an additional restraining mechanism on the movement ofthe carrier 70. However, the recessed slots 36 must be of dimensionssufficient to allow limited movement of the alignment tabs 75 during theraising and lowering of the apparatus 10 relative to the carrier 70.Additionally, tabs 38 can be mounted to the back face 24 to mate withalignment slots in the carrier 70 to further secure the carrier in theapparatus 10 subject, however, to the same dimensional requirementnecessary to allow relative movement between the apparatus 10 and thecarrier 70.

Two generally C-shaped handles 40 are used in a preferred embodiment tolift the apparatus 10 and have substantially right angles formed betweentheir intersecting legs. Preferably, the handles 40 are mounted parallelto each other in close proximity to the first and second sides, 32 and34, respectively, on the front face 22 of the body 20. In addition, thehandles 40 are horizontally aligned and symmetrically disposed about thevertical centerline, B--B, to provide handling stability. The separationand orientation of the handles 40 in this way prevents the use of theapparatus 10 with only one hand, which serves to reduce accidentaldumping of the wafers and injuries to personnel resulting from carelesshandling operations. The handles 40 are constructed using stainlesssteel in order to provide sufficient structural strength for handlingthe wafer carriers and are mounted by conventional methods, such asscrews. For example, 3/4" 300 Series stainless steel was found toprovide sufficient strength for use with handling eight inch diameterwafers in an eight inch long wafer carrier 70. While it is preferredthat a C-shaped handle 40 is used to provide for the distribution of theload over the body 20 as well as for stability, other handleembodiments, such as handles with only a single attachment point ormultiple handle embodiments, can be used within the scope of theinvention.

The arm 50 is preferably an elongated rectangular member extending fromthe back face 24 of the top portion 26 and having a top surface 52containing a lateral recessed portion 54, a fixed end 58 and a free end60 containing a slot 56. The fixed end 58 of the arm 50 is horizontallycentered along the vertical centerline, B--B, near the top of the topportion 26 and is mounted to the back face 24 of the body 20 atsubstantially a right angle using conventional methods, such as screws.The arm 50 must be constructed from a material of sufficient strength tosupport the weight of the carrier 70 and the wafers 80 during thehandling operations. For example, 3/4" thick polypropylene was found toprovide sufficient strength for use with handling eight inch diameterwafers in an eight inch long wafer carrier. The longitudinal centerline,shown as A--A, of the arm 50 extends substantially perpendicular to backface 24 and lies in a common plane with the vertical centerline, B--B,of the body 20. The slot 56 extends completely through the arm 50perpendicular to the top surface 52 dividing the free end 60symmetrically about the longitudinal axis A--A. The slot 56 extendslongitudinally from free end 60 toward the fixed end 58 and terminatesin the recessed portion 54. The edges of the free end 60 are preferablychamfered to facilitate the movement of the arm 50 through the carrierhandle 72 and the entry of the carrier handle support 78 into the slot56. The lateral dimension of the slot 56 is sized to allow a wafercarrier handle support 78 to move freely within the slot 56 in thelongitudinal direction, but serves to restrain lateral movement of thewafer carrier 70 parallel to the back face 24 of the body 20. Therecessed portion 54 serves to prevent longitudinal movement of the wafercarrier 70 that could result in damage to the wafers 80 from inadvertentcontact with the back face 24 of the body 20 or if the carrier 70 wereto slide off the arm 50 during the handling operations. Preferably, therecessed portion 54 extends laterally across the entire top surface 52and the longitudinal extent and the depth of the recess portion 54 aresized to receive and retain a wafer carrier handle 72 during handlingoperations. The recessed portion 54 is longitudinally positioned so thata wafer 80 contained in the wafer carrier 70 will be in close proximityto the back face 24 of the body 20 to prevent wafers 80 from sliding outof the wafer carrier 70 during engagement with the apparatus 10.Additional restraint mechanisms so as to more securely lock the carrierhandle 72 into place can be used in the present invention; however, theadditional restraints are not currently preferred because of the remoteuse of the apparatus 10.

In the operation of the present invention, the wafer carrier 70 that isto be moved is originally seated on support end 76. The apparatus 10 isattached to the carrier 70 by grabbing the handles 40 with two hands andinserting the arm 50 through the opening in the carrier handle 72 sothat the carrier handle support 78 is received in the slot 56 in thefree end 60 of the arm 50, which restricts movement of the carrier 70perpendicular to the slot 56. Insertion of the arm 50 through thecarrier handle 72 is continued until the carrier handle 72 is verticallyaligned with the recessed portion 54 of the arm 50 and carrier tabs 75mate with the tab slots 36 in the back face 24 of the body 20. When thecarrier handle 72 is aligned with the recessed portion 54, the handles40 are used to lift the apparatus 10 such that the carrier handle 72seats in the recessed portion 54, thereby preventing longitudinalmovement of the carrier 70 and the weight of the wafer carrier 70 andwafers 80 is supported by the arm 50, as shown in FIGS. 4 and 5. Theapparatus 10 and the carrier 70 can be moved in concert and the carrier70 repositioned as desired. The apparatus 10 can be disengaged from thewafer carrier 70 by placing the support end 76 on a supporting surfaceand lowering the apparatus 10 until the weight of the carrier 70 and thewafers 80 is no longer supported by the arm 50, but by the support end76, and the carrier handle 72 is no longer restrained in the recessedportion 54 of the arm 50. The arm 50 can then be withdrawn from withinthe carrier handle 72 and the carrier handle support 78 from the slot56.

Those of ordinary skill in the art will appreciate that the presentinvention provides great advantages over the prior art for lifting andtransporting vertically oriented carriers, especially when access to thecarrier is limited to a substantially horizontal direction. Inparticular, the subject invention greatly improves the stability andsafety of the handling operations, while simplifying the procedure forhandling. Also, because use of the apparatus involves a sequence of onedimensional steps, the present invention can be more easily integratedinto a fully automated procedure. Thus, the present invention canprovide for a reduction in the overall cost associated with theproduction of the wafers by providing for a more efficient procedure tomove bulk quantities of wafers between batch processes. While thesubject invention provides these and other advantages over otherapparatuses for handling wafer carriers, it will be understood, however,that various changes in the details, materials and arrangements of partswhich have been herein described and illustrated in order to explain thenature of the invention may be made by those skilled in the art withinthe principle and scope of the invention as expressed in the appendedclaims.

What is claimed is:
 1. A handling apparatus for a wafer carrier havingan upper handle defining an opening and at least one wafer slot, saidapparatus comprising:a body having a front face and a generally opposingback face; an arm extending from said back face, said arm having aportion configured to engage said opening in said wafer carrier handle,said arm having a recess therein configured to engage a surface of saidcarrier proximate to said opening, and said body extending generallyover all wafer slots, when said arm engages said carrier surface; and,at least one handle extending from said front face on each opposing sideof said arm.
 2. The apparatus of claim 1, wherein said at least onehandle comprises two handles extending from said front face and disposedon opposing sides of said arm.
 3. A handling apparatus for a wafercarrier, said apparatus comprising:a body having a front face, and agenerally opposing back face, said body including a wafer retainingportion; an arm extending from said back face, said arm having a wafercarrier restraining portion proximate to said back face; and, twohandles extending from said front face and disposed on opposing sides ofsaid arm.
 4. The apparatus of claim 3, wherein said body furthercomprises recessed slots and alignment tabs positioned in said back faceof said body.
 5. The apparatus of claim 3, wherein said wafer carrierrestraining portion includes a slot extending to a recessed portion insaid arm.
 6. The apparatus of claim 3, wherein:said body furthercomprises a middle support, said arm extending from one end of saidmiddle support; and, said handles extend from said front face and aredisposed on opposing sides of said middle support.
 7. The apparatus ofclaim 6, wherein said handles are oriented parallel to each other. 8.The apparatus of claim 6, wherein said handles are orientedsubstantially an equal distance from said middle support.
 9. Theapparatus of claim 3, wherein said handles are symmetrically positionedon opposing sides of said arm.
 10. A handling apparatus for a wafercarrier, said apparatus comprising:a rectangular body having a frontface, a generally opposing back face and a middle support; an elongatedarm extending from said back face proximate to one end of said middlesupport, said arm having a recess and a longitudinal slot extendingthrough said arm to said recess opposite said middle support; and, twohandles extending from said front face, said handles being symmetricallypositioned on opposing sides of said middle support and said arm.
 11. Acombination wafer carrier and detachable wafer carrier handlingapparatus, comprising:a wafer carrier including a base containing aplurality of wafer slots and a handle extending from an end of saidwafer carrier defining an opening between said handle and said base;and, detachable wafer carrier handling apparatus comprising:a bodyhaving a front face and a generally opposing back face; an arm extendingfrom said back face, said arm having a portion configured to engage saidopening in said wafer carrier handle, said arm having a recess thereinconfigured to engage a surface of said carrier proximate to saidopening, and said body extending generally over all wafer slots, whensaid arm engages said carrier surface; and, at least one handleextending from said front face on each opposing side of said arm. 12.The apparatus of claim 11, wherein said body defines a plane includingsaid back face having dimensions that are substantially equal to or lessthan the corresponding dimensions of said wafer carrier.
 13. Theapparatus of claim 11, wherein:said carrier further comprises alignmenttabs; and, said body further comprises recessed slots positioned in saidback face of said body and adapted to mate with said alignment tabs onsaid carrier.
 14. The apparatus of claim 11, wherein:said carrierfurther comprises a carrier handle support extending between said baseand said handle; and, said arm contains a slot having dimensions toslidably receive said handle support.
 15. The apparatus of claim 11,wherein said at least two handles comprises two handles symmetricallypositioned on opposing sides of said middle support and said arm. 16.The apparatus of claim 11, wherein:said body further comprises a middlesupport, said arm extending from said middle support proximate to oneend of said middle support to support said wafer carrier with said waferslots opposing said back face; and, said handles are symmetricallypositioned on opposing sides of said middle support.
 17. A method ofhandling a vertically oriented wafer carrier having an upper handledefining an opening and at least one wafer slot, said methodcomprising:providing a handling apparatus having a body with a frontface and a generally opposing back face, an arm extending from the backface, the arm being configured to engage the opening in the handle, thearm having a recess therein configured to engage a surface of thecarrier proximate to the opening, the body extending generally over allwafer slots, when the arm engages the carrier surface, and, at least onehandle extending from the front face on each opposing side of the arm;inserting the arm through the opening in the handle; engaging thesurface on the wafer carrier in the recess in the arm; and, handling thewafer carrier using at least one handle on each opposing side of thearm.
 18. The method of claim 17, wherein the wafer carrier includes ahandle support attached to the handle and extending across the opening,and, wherein:said providing further comprises providing the arm with aslot sized to slidably receive the handle support; and, said insertingfurther comprises inserting the arm into the opening to slidably receivethe handle support in the slot.
 19. The method of claim 17, wherein saidhandling comprises handling the wafer carrier using one handle on eachopposing side of the arm.
 20. The method of claim 17, wherein saidproviding further comprises providing the body with a middle supportextending generally over all wafer slots and the arm extends from themiddle support.